"Scaling Up Affordable Health Insurance: Staying the Course" is the fifth volume in a series of in-depth reviews on the role of health care financing in improving access for low-income populations to needed care, protecting them from the impoverishing effects of illness, and addressing the important issues of social exclusion in government financed programs. Success in improving access and financial protection through community and private voluntary health insurance have led many countries to attempt to make membership compulsory and to offer subsidized insurance through the public sector. The protagonists are divided into several camps; from supporters of health insurance to opponents or skeptics. Today many low- and middle-income countries are no longer listening to this dichotomized debate between vertical and horizontal approaches to health care. Instead, they are experimenting with new and innovative approaches to health care financing. Health insurance is becoming a new paradigm for reaching the Millennium Development Goals. The research for this volume shows that when properly designed and coupled with public subsidies, health insurance can contribute to the well-being of poor and middle-class households, not just the rich. And it can contribute to development goals such as improved access to health care, better financial protection against the cost of illness, and reduced social exclusion. The book is organized into three main parts. Major policy directions in financing health care are discussed in Part 1, with a particular focus on the pre-conditions for scaling up. Part 2 moves from theory to practice with overviews and country level studies on health insurance development. Finally, part 3 highlights the implementation challenges.